(Tribune Media Services) -- Kay Rihn reserves a nonrefundable rental car through Hotwire and uses a payment system that allows her to send a check. When she doesn't receive a confirmation from the online agency, she mails a check anyway. Turns out she doesn't have a reservation. But her money? It's gone.

Q: I'm having trouble with a car rental reservation that never went through. I thought I had secured a reservation through Hotwire.com for a car in St. Petersburg, Florida, using its "bill me later" option.

When I printed out the details, I notice that there was a 19.99 percent interest rate if payments weren't made within 25 days. I waited for an invoice, and when I didn't get one, I just mailed a personal check to Hotwire.

On the day of my trip, I called Hotwire to double-check my reservation. That's when I discovered there was none.

I checked to see if the check was debited from my account, and sure enough, it was. I immediately called Bill Me Later and asked them to return my money. They seemed agreeable, and asked me to fax all the pertinent information. A customer service representative said it would take five to seven business days to respond.

It's now been several weeks, and I haven't heard from Bill Me Later. I've contacted Hotwire and faxed them all the details. I've also been in contact with them by phone, but a manager said there was nothing they could do for me.

I don't think I should pay $387 for a car I never got. Is there anything you can do to help me?

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A: Hotwire should have refunded your purchase weeks ago. Bill Me Later is just another payment option, but the way you paid for the car shouldn't really matter. You deserve your $387 -- now.

Cars booked through Hotwire are nonrefundable. And, unless you're paying through Bill Me Later, your credit card is charged for the rental immediately. Bill Me Later is a third-party site that allows you to postpone your payment, but you have to read the fine print carefully, which you did.

But maybe you should have kept reading. One of the frequently asked questions on the site addresses your situation. "If you are expecting a billing statement and have not received it, there could be a problem with the billing address we have on file," it says. "Please login to view or change your address."

When you're booking travel online, assume nothing. And when you're booking travel through multiple services (say, a car rental company, an online travel agent and a third-party payment service) assume something will go wrong. Maybe I'm being a little dramatic, but whenever your money changes hands so many times and you're using an intermediary like an online agent, the odds of something going wrong certainly increase.

You should have phoned Hotwire when you didn't receive a confirmation of your purchase. I've used Hotwire to book rental cars, and I usually get an email from the site within five minutes of clicking the "book" button. Waiting a few days and then sending a check was probably the wrong move -- even if you were looking at a 19.99 percent interest rate (which, by the way, is a tad high).

Unless you have an email that confirms your car, you shouldn't be paying anyone. When it became apparent that Bill Me Later had your money and you had no reservation, you should have not only contacted Hotwire and Bill Me Later, but also your bank. If you catch a mistake like this early enough, your bank can stop payment on a check.

I contacted Hotwire on your behalf. It asked Bill Me Later about your money, and you've been sent a full refund.